A CUSTOM NEWS FEED By the time Bridget Baker, who works in public relations in Seattle, checks Google Reader while eating lunch at her desk, she has already read most of the articles in her feed because she saw them on Twitter.

People with shared interests become your editor and Twitter becomes an alternative RSS feed.

One-fifth of posts and 57 percent of repeat messages contain a link, proving that this is an increasingly popular way to spread news, said Dan Zarrella, a social media scientist who works at a software company called HubSpot.

"People's social worlds are enhanced by new communication technologies.

"People use the technology to stay in touch and share information in ways that keep them socially active and connected to their communities."

Social scientists have a name for this sort of incessant online contact. They call it “ambient awareness.” It is, they say, very much like being physically near someone and picking up on his mood through the little things he does — body language, sighs, stray comments — out of the corner of your eye.

Each little update — each individual bit of social information — is insignificant on its own, even supremely mundane. But taken together, over time, the little snippets coalesce into a surprisingly sophisticated portrait of your friends’ and family members’ lives, like thousands of dots making a pointillist painting. This was never before possible, because in the real world, no friend would bother to call you up and detail the sandwiches she was eating. The ambient information becomes like “a type of E.S.P.,” as Haley described it to me, an invisible dimension floating over everyday life.“It’s like I can distantly read everyone’s mind,” Haley went on to say. “I love that. I feel like I’m getting to something raw about my friends. It’s like I’ve got this heads-up display for them.” It can also lead to more real-life contact, because when one member of Haley’s group decides to go out to a bar or see a band and Twitters about his plans, the others see it, and some decide to drop by — ad hoc, self-organizing socializing. And when they do socialize face to face, it feels oddly as if they’ve never actually been apart. They don’t need to ask, “So, what have you been up to?” because they already know. Instead, they’ll begin discussing something that one of the friends Twittered that afternoon, as if picking up a conversation in the middle.

You could also regard the growing popularity of online awareness as a reaction to social isolation, the modern American disconnectedness that Robert Putnam explored in his book “Bowling Alone.” The mobile workforce requires people to travel more frequently for work, leaving friends and family behind, and members of the growing army of the self-employed often spend their days in solitude. Ambient intimacy becomes a way to “feel less alone,” as more than one Facebook and Twitter user told me.

What's the social utility to Facebook—why should you join? Like with e-mail and cell phones, there are many, and as you begin to use it, you'll notice more and different situations in which it proves helpful. In general, Facebook is a lubricant of social connections. With so many people on it, it's now the best, fastest place online to find and connect with a specific person—think of it as a worldwide directory, or a Wikipedia of people. As a result, people now expect to find you on Facebook—whether they're contacting you for a job or scouting you out for a genius grant.

True, you might not want people to be able to follow your life—it's no great loss to you if your long-lost college frenemy can't find you. But what about your old fling, your new fling, your next employer, or that friend-of-a-friend you just met at a party who says he can give you some great tips on your golf swing? Sure, you can trade e-mail addresses or phone numbers, but in many circles Facebook is now the expected way to make these connections. By being on Facebook, you're facilitating such ties; without it, you're missing them and making life difficult for those who went looking for you there.

Short, continuous, low-content updates about the particulars of your friends' lives—Bob has the flu, Barbara can't believe what just happened on Mad Men, Sally and Ned are no longer on speaking terms—deepen your bonds with them. Writer Clive Thompson has explored this phenomenon, what social scientists call "ambient awareness." Following someone through his status updates is not unlike sitting in a room with him and semiconsciously taking note of his body language, Thompson points out. Just as you can sense his mood from the rhythm of his breathing, sighing, and swearing, you can get the broad outlines of his life from short updates, making for a deeper conversation the next time you do meet up.It's this benefit of Facebook that seems to hook people in the end: Their friendships seem to demand signing up.

The business of information management—helping organisations to make sense of their proliferating data—is growing by leaps and bounds.

The business of information management—helping organisations to make sense of their proliferating data—is growing by leaps and bounds. In recent years Oracle, IBM, Microsoft and SAP between them have spent more than $15 billion on buying software firms specialising in data management and analytics. This industry is estimated to be worth more than $100 billion and growing at almost 10% a year, roughly twice as fast as the software business as a whole.

a new kind of professional has emerged, the data scientist, who combines the skills of software programmer, statistician and storyteller/artist to extract the nuggets of gold hidden under mountains of data. Hal Varian, Google’s chief economist, predicts that the job of statistician will become the “sexiest” around. Data, he explains, are widely available; what is scarce is the ability to extract wisdom from them.

Across the internet economy, companies are compiling masses of data on people, their activities, their likes and dislikes, their relationships with others and even where they are at any particular moment—and keeping mum.

“They are uncomfortable bringing so much attention to this because it is at the heart of their competitive advantage,” says Tim O’Reilly, a technology insider and publisher. “Data are the coin of the realm. They have a big lead over other companies that do not ‘get’ this.”

Amazon and Netflix, a site that offers films for hire, use a statistical technique called collaborative filtering to make recommendations to users based on what other users like. The technique they came up with has produced millions of dollars of additional sales. Nearly two-thirds of the film selections by Netflix’s customer come from the referrals made by computer. EBay, which at first sight looks like nothing more than a neutral platform for commercial exchanges, makes myriad adjustments based on information culled from listing activity, bidding behaviour, pricing trends, search terms and the length of time users look at a page. Every product category is treated as a micro-economy that is actively managed. Lots of searches but few sales for an expensive item may signal unmet demand, so eBay will find a partner to offer sellers insurance to increase listings. The company that gets the most out of its data is Google. Creating new economic value from unthinkably large amounts of information is its lifeblood. That helps explain why, on inspection, the market capitalisation of the 11-year-old firm, of around $170 billion, is not so outlandish. Google exploits information that is a by-product of user interactions, or data exhaust, which is automatically recycled to improve the service or create an entirely new product.